Acoustical device



A ril H6, 1929, H, P M HREY E,709,485

ACOUSTIC AL DEVICE Filed March 26,, 1927 2 Sheets-Sheet 1 INVENTOR Ap 16, 192. PUMPHREY 1,709,485

AcousTIcAL DEVICE Film mm 26, 1927 BShetw-Sheet 2 Ill/VENTOR Patented A r. 1 1929.

\UNITED STATES WALTER HYER PUMPHREY, F PLEASANT PLAINS, NEW YORK, ASSIGNOR TO A.

PATENT OFFICE.

onEBE & 00., 1110., or mcnmonn HILL, NEW YORK, A conroim'rlon or nnw You.

, ACOUSTICAL DEVICE.

Application filed March 26, 1927. Serial No. 178,798. 1

y invention relates generally to acoustical devices and, while not limited in its application, is shown in the present embodiment applied for use as a loud speaker of the type now commonly employed with radio receivers.

A construction'suitable for carrying my invention into effect is illustrated in the accompanying drawings, in which- Fig. 1 is a view in side elevation of the speaker, with portions broken away to expose the interior construction and arrangement; v

Fig. 2 is a detail perspective view showing peripheral portions of the separated diaphragm members; I

Fig. 3 is a detail elevation of a peripheral portion of one of the diaphragm members, etc.

Fig. 4 is a View similar to Fig. 2, showing a slight modification, and

Fig. 5 is a detail sectional view illustrating a further modification.

- Referring tothe drawings, the loud speaker is shown carried by a support of a form suitable for being placed upon a table, cabinet or the like but it will be understood that this is merely illustrative and that any other type of support may be substituted or it may be entirely dispensed with, as, for example,

when the speaker is hun on the wall of a room or ,built in the cabinet of a radio receiver. I V

, As shown, the supportcomprises a ring- I shaped body 1, provided with aremovable closure plate 2, covering the opening in the? ring and a pedestal or base 3.

Mounted on the support, there is a diaphragm formed of two members 4 and 5, so

' 4o shaped and relatively arranged as to provide an air chamber 6, between them.

The front diaphra m member 4 is shown as a shallow cone of paper or other light weight material, preferabl reinforced at the apex, as indicatedat 7. ile this form and construction is comparatively-simple and'inexpensive to manufacture, presents an agreeab e appearance and 'ves satisfactory results, I do not wish to understood as confining myself to its use or makingjt essential to the practice of the invention,-as other forms may be employed, if desired, which will give equallygood results. y

The rear diaphragm member 5 is shown of shallow frusto-conical form and has a rear opening 8, formed therein of about the diameter of the opening in the ring body 1 of the support, to which the diaphragm member is secured by a clamp ring 9, or other suitable means. I make the same reservation as to the form, construction, etc., of this rear diaphragm as made above with reference to the front member and while it is preferably con-.

structed of paper, I do not confine myself to it, as other materials may be employed to give equally good results.

As shown, the two diaphragm members are of the same or substantially the same diameter and are oppositely disposed, in separated relation, to form an annular opening 10, between their adjacent peripheral edges, I

providing a communicating assage between the body of air in the diap ragm chamber and the outer air.

In order to space the dia hragm members a definite distance apart and operatively connect them in such spaced relation, without seriously obstructing the opening between them, I may use a glued instrip of corrugated paper 11, as shown in Figs. 1 to 4, or light weight hollow rivets 12, as shown in Fig. 5 or otherwise secure them together.

Mounted within the diaphragm chamber and carried by the ring of the support, there is an electro-magnetic driver 13 of any suitable or well known type, which isconneoted in the usual manner through a rod 14 and setscrew 15, with the reinforced apexof the front diaphragm member.

The disk 2, formin ,the removable closure for the opening in t e ring support, gives convenient access to the driving element for examination, adjustment, removal or repair.

The driving element 13', is energized by being connected in circuit in'the usual manner with the outlet end of the radio receiver with which the loud speaker is used and thus ar-' ranged imparts vibratory motion which is amplified by the diaphragm.

. The effective operationof the loud speaker,

and by that is meant the greatestvolume of tone of most pleasing quality, appears to re; quire free and unobstructed communication phragm chamber and the outer air and as it is believed to be of importance that this freedom of communication be equalized throughout the diaphragm, the annular peripheral o ening between the members isprovided as ahove described and is preferred over a strucbetween the body of confined air in the diaturally equivalent scheme of forming a circular series of openings adjacent the periphery of either or both the diaphragm members.

.The many important advantages of the invention'will be apparent to those skilled in the art from the foregoing description.

"Having thus described my invention, what I claim is: i

1. An acoustical device comprising a diaphragm formed of front and rear members relatively arranged to provide an air chamr parting motion to the diaphragm.

3. An acoustical device-comprising a diaphragm formed of front and rear oppositely coned members relatively arranged to provide an air chamber between them, means connecting themembers in separated relation to form an annular opening adjacent their peripheral edges, and a driving element for imparting motion to the diaphragm.

4. An acoustical device comprising a diaphragm formed of front and rear oppositely coned members relatively arranged to provide an air chamber between them, means connecting the members in separated relation to form anannular opening adjacent their peripheral edges, anda driving element located within the, air chamber for imparting motion to the diaphragm.

5. An acoustical device comprising a chambered diaphragm formed of oppositely disposed front and rear members of approximatel equal'diameter, means connecting the periplieries of the diaphragm members in separated relation to providean annular opening between their adjacent circumferentlal edges, and-a driving element for imp art- 'ing motion to the diaphragm.

6. An acoustical device comprising a chambereddiaphragm formed of oppos tely disposed approximately conical members of substantially the same diameter, means connecting the diaphragm members at their peripherles 1n separated relation, and a driving element for imparting motion to the diaphragm. 7 An acoustical device comprisin a chambered diaphragm formed of oppositely dis posed approximately conical members of substantially the same diameter, means connect-- ing the diaphragm members at their periphcries in separated relation, and a driving element mounted between the diaphragm members and connected to one of said members.

8. An acoustical devicecomprising a diaphragm formed of front and rear members connected in separated relation to provide a communicating opening between the bod of air between the members and the outer air, a

driving element mounted between the mem-f bers and connected to one of them and a removable section closing an opening in the rear diaphragm member giving access to the driving element.

9. An acoustical device comprising a diaphragm formed of front and rear members, means connecting the diaphragm members in fixed separated relation to provide a communicating passage between the body of air between themembers and the outer air, a driving element connected ,to one of the diaphragm members, and a suitable support for the diaphragm. v

10. An acoustical device comprising a diahra m formed of front and rear members P t: 7

permanent connecting means for definitely spacing the members apart at their adjacent edges to provide communication between the body of air between the members and the outer air, a support for the diaphragm, and a drivin element mounted on the support and operatively. connected to one of the diaphragm members. r

11. An acoustical device comprising a diaphragm, angularly disposed wall for forming an air chamber extending substantially through the area of one side of the diaphragm and communicating with the outer air only adjacent the periphery thereof and a driving element for imparting motionto the diaphragm.

12. An acoustical device comprising a diaphragm formed of front and rear members permanently secured together in spaced relation and shaped to provide an air chamber between them of such form asto communicate with the outer air only adjacent the periphery of the diaphragm and a driving element for imparting motion to the diaphragm.

- WALTER HYER PUMPHREY.

CERTIFICATE or CORRECTION,

Patent No. 1,709,485. Granted April 16, 1929, to

WALTER HYER PUMPHREY.

It is hereby certified that error appears in the printed specification of the above numbered patent'requiring correction as follows: Page 2, line 96, claim 11, for the wordf'wall" read "walls"; and that the said Letters Patent should be read withthis correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed'th'is 2nd day at duty, A, K929.

j M. .15., Moore, (Seal) 7 Acting Goissioner oi Patents.

CERTIFICATE or CORRECTION.

Patent No. 1,709,485. Granted April 16, 1929, to

WALTER HYER PUMPHREY.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 2, line 96, claim 11, for the word "wall" read "walls"; and that the said Letters Patent should be read with this correction therein that the same may conform to the record. of the case in the Patent Office.

Signed and sealed this 2nd day of July, A. D. 1929.

M. J. Moore, (Seal) Acting Commissioner of Patents. 

